Earth’s Interior

Chapter 5 Section 1

Earth’s Interior

Geologists learned about Earth’s interior:

• Directly from rock samples– Info from rocks that come to the surface

DrillingNaturalForces

Earth’s Interior

• Indirectly from seismic waves (earthquakes)– Waves from earthquakes will change speed and

direction when traveling through different densities

Temperature • Top 20m are cool

• Temperature raises as you go deeper

• Heat is left over from formation of Earth and radioactive substances

Pressure increases as you go deeper

Earth’s Structure

• Crust – outermost layer– Solid rock that includes dry land and ocean

floor– Between 5 and 40 km thick (mountains 70km)– Oceanic crust is mostly rocks like basalt

(dark, fine texture)– Continental crust is mostly

rocks like granite

(light, coarse texture)

Earth’s Structure

• Mantle – thickest layer– 3000km thick– Very hot solid rock– Divided up by physical characteristics

• Lithosphere – upper part of mantle (1000km)• Asthenosphere – less rigid (plastic like)• Lower mantle – solid material that extends to core

Earth’s Structure

• Core – Earth’s center– Made mostly of Fe and Ni– Liquid outer core and solid inner core– Scientists think that movement of the liquid

core creates a

magnetic field

Brain pop